An exhaust system is used to conduct away an exhaust gas produced by the internal combustion engine and has been known for a long time from the prior art. The exhaust gas of the internal combustion engine can contain undesirable or harmful constituents, which must be reduced or which should be removed from the exhaust gas before the exhaust gas exits into the environment. To this end, an exhaust gas treatment device is usually provided, which has an exhaust gas treatment chamber through which the exhaust gas can flow and which is enclosed by a housing of the exhaust gas treatment device. A catalyst and/or particle filter is generally arranged inside the exhaust gas treatment chamber in order to clean the exhaust gas of the said undesirable and harmful constituents. Such an exhaust system can be designed in a two-streamed manner from the internal combustion engine to the exhaust gas treatment device and correspondingly have two exhaust gas feed lines, which conduct the exhaust gas produced by the internal combustion engine in separate streams to the common exhaust gas treatment device, the respective exhaust gas feed line being fluidically connected to the exhaust gas treatment device. The fluidic connection of the respective exhaust gas feed line is usually realised in such a manner that the exhaust gas feed lines run substantially parallel to the exhaust gas treatment chamber and open into the exhaust gas treatment chamber in parallel.
The disadvantage of this is that the exhaust gas conducted by the respective exhaust gas feed line runs separately inside the exhaust gas treatment chamber, especially at high speeds of the exhaust gas, which can sometimes be up to ⅔ the speed of sound and higher, and is thus not mixed and does not flow through the exhaust gas treatment chamber uniformly. However, mixing of the exhaust gas conducted away by the respective exhaust gas feed line before flowing through the respective catalyst and/or particle filter, and/or a uniform flow through the respective catalyst and/or particle filter is desired in order to ensure for example uniform treatment of the exhaust gas. Furthermore, the exhaust system can have a measurement device downstream of the exhaust gas treatment device, which measurement device measures certain constituents of the exhaust gas such as the concentration of nitrogen oxides. A virtually separate flow of the exhaust gas conducted by the exhaust gas feed line through the exhaust gas treatment device does not however permit any reliable statements about the measured values, because in case of doubt, that is, in particular in the case of two-streamed exhaust systems and correspondingly high speeds of the exhaust gas, it would only be possible to attribute the said measured values to one of the respective exhaust gas feed lines.